This invention relates to disk memory cartridges in general, and specifically to medium to small size disk memory cartridges adapted to be removably attached to an associated disk drive mechanism having a drive spindle.
Many current generation hard disk cartridges used in the data processing industry are designed to be removably attached to an associated disk drive unit. The removable disk cartridge typically includes a housing, a hard or rigid disk mounted within the housing, an externally accessible hub connected to the disk to be rotated by an externally located drive spindle, and an access door for enabling the Read/Write transducers located in the disk drive unit to be inserted into and removed from the interior of the disk cartridge. In medium to small disk cartridges, e.g., cartridges having a diameter of no more than eight inches, the access door is typically slidably arranged at the insertion end of the cartridge, and is spring biased to automatically move to a closed position in which the transducer access port is blocked by the door when the cartridge is not inserted into the disk drive unit.
In order to preserve the integrity of the delicate disk recording surfaces, a hub locking mechanism is typically incorporated into such disk cartridges which normally clamps the hub, and thus the disk, in a fixed position when the cartridge is not seated on the disk drive spindle. When locked in this position, the disk surfaces are rigidly maintained in non-contacting relationship with the internal components of the cartridge to preclude the possibility of the disk surface being scratched. The hub locking mechanism typically includes a release member engagable with a small pin or post carried by the disk drive unit. Whenever the cartridge is inserted into the disk drive unit in close proximity to the drive spindle, the pin progressively engages the release member to relieve the clamping force on the hub and thus permit the disk to be freely rotated within the cartridge housing by the drive spindle. Typical hub locking mechanisms employ two lever plates each having an inner edge margin providing an interference fit with an inner hub flange located in the interior of the cartridge housing, a pair of compression springs for spring loading the lever plate within the housing and a pair of fasteners such as bolts, for capturing the compression springs and securing the lever plate against rotation within the cartridge housing. Such an arrangement, while operable, requires assembly steps which are time consuming and somewhat delicate to perform which adds increased cost to the disk cartridge. In addition, several assembly components are required in order to provide convenient reference mounting posts for the compression springs, a pivot point for the lever plate, and abutment referencing surfaces, all of which complicates the design of known hub locking mechanisms.